code: def test_dynamic_streams_refresh(self):
      stream = PointerXY(x=0, y=0)
      dmap = DynamicMap(
          lambda x, y: Points([(x, y)]), kdims=[], streams=[stream]
      )
      plot = mpl_renderer.get_plot(dmap)
      pre = mpl_renderer(plot, fmt="png")
      plot.state.set_dpi(72)
      stream.event(x=1, y=1)
      post = mpl_renderer(plot, fmt="png")
      self.assertNotEqual(pre, post)
  
file_path: holoviews/holoviews/tests/plotting/matplotlib/test_callbacks.py
imports: from collections import deque
  import numpy
  from holoviews.core import DynamicMap
  from holoviews.element import Curve, Points
  from holoviews.streams import PointerX, PointerXY
  from .test_plot import TestMPLPlot, mpl_renderer
label_desc: Use image node_id 1 for calling the TestCallbackPlot obj's underlying member method code with example usage: obj.test_dynamic_streams_refresh() without return types